The goal of this research is to study the molecular mechanisms involved in controlling testicular physiology and male reproduction. Aim 1 will investigate the control of transcription of the rat inhibin a-subunit gene by GATA-binding proteins in MA-10 cells and rat Sertoli and Leydig cells, and will identify cofactors and cell-specific proteins that interact with GATA-1 to regulate the a-subunit gene. Aim 2 is to investigate the regulation of two promoters within the rat bB-subunit gene that give rise to two species (4.8- and 3.7-kb) of the bB-subunit mRNA from alternate initiation sites. Aim 3 will investigate the developmental expression and hormonal regulation of GATA-binding proteins in the rat testis to determine whether any observed changes correlate to the known regulation of the a- and bB-subunit genes.